Stone-crushing machine.



T. G. RENNERFELT. STONE CRUSHING MACHINE. APPLICATION FILED MAR 25, 1913' 1,141,581 a Patented June 1, 1915.

H ;EIIIIIII"- TUBE GUSTAlE RENNERFELT, 0F STOCKHOLM, SWEDEN.

STONE-GBUSHING MACHINE.

spring between the'jaw and the frame and a toggle joint between the jaw and the frame arranged to be operated through a pitman from an eccentric formed on the driving shaft in such manner that the aw is given a swinging motion adapted to cause the crushing of the stones between the jaw and the framethis type of machine being known as the Blake crusher. Machines of this type are necessarily constructed so that the diameter of the eccentric is very large compared with its useful eccentric radius, and as a consequence the mechanical efficiency of the machine is lowfrequently so low that more than one half of the power applied for driving the machine is lost in the three bearings of the eccentric. The eccentric becomes exposed to very high pressures which frequently cause excessive heating and wear of its journals and bearings, and sometimes even break the driving shaft. The ability .of the said toggle joint, peculiar to the Blake crusher, to transmit pressure to the levers of the toggle joint in such way that this ability is greatest when said angle is at a maXimum 6. when the levers stand most nearly to a straight linebut at that moment the crushing of the stones between the jaw and the frame is'already accomplished, so that in fact the toggle joint stands in a position to apply its greatest force at the moment when the force is least required. At the moment when the greatest force is needed for crushing the large stones the angle between the levers is more acute, and consequently the force of the toggle joint diminished. Machines of this type also suffer from the fact that the ends of the two levers of the toggle joint are so located that it is difficult to supply themiwith the proper lubrication, this difiiculty being especially serious since undue friction at those parts Specification of Letters Patent.

Patented June 1, 1915.

Application filed March 25, 1913. Serial No. 756,791.

may cause-especially if the spring is weaka reversal of the normal direction of pressures upon the bearings of the eccentric. Since there is always some play in these hearings such reversals will cause shocks which are disagreeably noisy and greatly other uncrushable steel tools which acci dentally drop between the jaws of the stone crusher in spite of reasonable care.

The object of my invention is to obviate the aforesaid difiiculties and to provide a stone crusher of high mechanical efiiciency, which shall be reliable in operation and require a comparatively small amount of driving power, in which the bearings shall not be liable to heat, and of which no part which is expensive or diflicult to replace shall be broken in case of excessive overload. My improved stone crusher will also possess the advantages that it is'of shorter length and smaller bulk than crushers of the above mentioned type, and by reason of its higher efliciency it will require a flywheel of comparatively small weight. These advantages are of importance, since such crushers must frequently be transported along rough country roads. 7 jaw depends on the angle between the two In order to gain the aforesaid objects I use in my improved stone crusher no toggle joint and no eccentric with small eccentric radius. I employ instead a mechanism comprising an unequal armed lever and a roller, together with means for swinging the lever back and forth, the lever being fulcrumed in the frame, and the roller placed so that it can roll back and forth between the free end of the jaw and the shorter arm of the lever.

My invention is illustrated in the accompanying drawings in which Figure l is a vertical sectional view of a stonecrusher made according to my invention. Fig. 2 is a side view of the lever as seen in the direction of the arrow in Fig. 1.

Referring to the drawings in detail 2 represents the frame of the crusher, and 3 a plate of hard material fastened to the frame and thus constituting a part of the frame.

4: represents another hard plate fastened to the'jaw 5 which by means of the shaft 6 is journaled in 'theframe;

7 represents the lever, formed in two parts kepttogether' by the hinge 8 and the bolts or rivets 9. The fulcrum of the lever is formed by around steel bar 10, fastened to V the lever by rivets 11 (Fig; 2.). The bar ing rod 16, the other end ofwhich is jourrests on a concave face formed in a block 12 mounted slidably in the frame so that its distance from the-plate 3 may be varied by inserting between the block and the frame a filler ltof suitable thickness. The

top end of'the lever is connected through the pin15'to one end of the link or connect naled on the crank 17 of a shaft whichis journaled in the frame between the jaw and i the lever. The throw of the crank is shown dotted lines.

in Fig. 1 of about twice the diameter of the shaft, so that upon rotation of the crankshaft the lever 7 will oscillate between the formed at the lower end of the jaw 5. A spring (or springs) 21 applied between the jaw and the frame serves to keep the jaw The plate infirm contact with the roller. I 22 fastened to the jaw serves to facilitate 1 the introduction of the roller 19 to its proper and. 25a flywheel keyed to the driving shaft. 7

place when the machine is assembled, butdoes not come into contact with the roller during the operation of the machine.

represents an oilcup for lubricating the fulcrum of the lever, 24: is a sheet iron cover,

26, 27 represent wheels upon which the machine may be mounted to facilitate its transportation on a road. The upper and lower parts of the lever, kept together by the aforesaid hinge 8 and bolts 9, are separated by a gap 28, across which the stud 29 extends, being fastened in the upper part and pressing with its end against the lower part.-

The machine operates in the following manner: Power is applied to the driving shaft'in suitable manner for instance by a belt on the flywheel, and upon rotation of said shaft the lever 'is set into a swinging -or oscillating motion, its upper end moving through along distance back andforth, and its lower end below the fulcrum moving a much shorter distance by reason of the great ratio between thelengths of the two lever arms. The motion .of the lever is transmitted through the roller to the jaw which, being pivoted on the shaft 6, will swing in the manner customary'in a stone crusher and break the stones which are dropped between the plates 3 and 4. During this operation the roller 19 will roll be' tween thev concave face 20 and theconvex face of the shoe 18, and no sliding'friction, will exist at the points of contact. between the roller and said-faces; for this reason the roller requires no lubricant. The'bar 10,

V which constitutesthe fulcruin of the lever,

is supported along its whole length upon the block 12, and issubjected merely to pressure and not to any'bending moment. For this reason the diameter of the bar- 10 maybe comparatively small, which is important because it is necessary for the efficient op-- eration of the machine that the friction .at"

thefulcrum; of the lever shall be small enough to permit the springs 21to swing the" lever around its fulcrum; so thatthe pressures upon the pin15 indicated by the arrow and-upon the crank 17 shall never reverse their normal directions. This result can be accomplished with reasonably. strong;

springs, even though the lever 'armis quite short,'-p rovided that the friction at the fulcrum is small, and "in order to avoid this friction entirely I prefer in some cases-to form theconcavity in the block 12 with a '95 the radiusof the bar 10 so that. said bar I will'have a rolling motion upon said concavity, and no sliding friction atall will exist at the fulcrum. In such .cases it is;

radius of curvature which is greater than however necessary that theangular oscillation of the lever, orv the "ratio between the throw of the crank and the length of the longer lever arm, shall be limited to a certain value depending on the radius of curva: i r

ture in the blockandjon the coefficient of friction thereon in 'a manner which will be understood by those versed in the art. This 1 construction witharolling fulcrum is preferable in very' large machines, but for, .J V

smaller machines I'prefer to have a greater oscillation of the lever, and to'keep the fric 7 tion low atthe fulcrum by means of good lubrication. 7 The radius of curvature face 20should'be large enough to permit the roller to roll without slipping, and small enough to keep therol-ler in its properplace:

' I t will be noted thatithe. bolts 9 are so 10- cated, that during the operation of'the ma-' H chine they; will be subjected to tension. Their combined sectional "area is great enough to stand thestrain due to normal operation, but they possessless relative of the concave strength than any other part of the machine,

so that when the 'crusher'is subjected to an excessive overload, caused for instance by a Sledgehammer between'its jaws,- the said bolts will be pulled off. 7 The motionfof the jaw and the lower part-of the lever'will thenj cease while the motion of the flywheel, the

crankshaft and the upper part of the lever will go on, until the driving power be disconnected. During this time the upper part of the lever is guided by the aforesaid hinge 8, so that it cannot strike against the jaw or the cover. By reason of the gap 28 the upper part of the lever will not strike against the lower part; the aforesaid stud 29 will receive the firstblow and thereby become upset compressed or crushed so that further shocks or blows will not Occur.

I do not limit my claims to the details of construction shown in the drawings, since many modifications can be made therein and still come within the scope of my invention. For instance the curvature of the shoe 18 is shown in the drawings such, that the ratio between the effective lever arms is nearly constant during the whole stroke of the lever, but it can evidently be so chosen that this ratio is greater in the beginning than at the end of the stroke. I can also use a plurality of rollers instead of a single roller 19, or I can use balls instead of rollers. It is also evident that the cylindrical bar 10 could belong to the block 12 and a concavity corresponding to such a bar could be formed in the lever. In some cases a shoe ofrolled material may be applied to the face 20, and all such modifications are intended to be covered by my claims.

From the foregoing it will be observed that the roller 19 is located between a convex surface on the lever 7 and aconcave surface on the jaw 5; and that the arrangement and relative dimensions may be such that thecenter of curvature of the said convex surface may be so located below the fulcrum that it will oscillate on both sides of a vertical line passing through said fulcrum, so that the instantaneous leverage of the short arm of the lever 7 remains substantially constant, and therefore excessive and abnormal strains on the member 17 are avoided.

It will be further observed that the center of curvature of the concave surface 20 and roller 17 are located on a substantially vertical line below the shaft 6, so that the roller moves in substantially a straight line, and that it is located sufliciently low for a line passing through the centers of pressure on said roller to also pass through, or near, the lower ends of the jaw members 3 and 4:. It results from this structure that the'strains on the shaft 6 can never reverse in direction which often occurs with disastrous results in other types of rock crushers. Again, the strains on the roller 19 are so great that it wears rapidly if it is allowed to slide. By the construction above, however, there is little tendency for it to move up and down, and it consequently rolls through the distances moved, thus causing it to wear round instead of fiat.

Having thus described my invention, what- I claim is:

1. The combination of a frame; a jaw provided with a concave surface journaled in the frame; a lever having a fulcrum in the frame; said lever having a convex face a roller mounted loosely between the said concave surface and the said convex face; and means for oscillating the lever; the center of curvature of the convex face being located substantially vertically below the ful- CIUID. of the lever.

2. The combination of a frame; a jaw having a concave surface journaled in the frame; a lever fulcrumed in the frame; said lever having a convex face; a roller held by friction between the said concave surface and the said convex face; and means for swinging the lever back and forth; the center of curvature of said concave surface as well as said roller being located in a substantially vertical line passing through the j ournal of said jaw, whereby said roller may move in a substantially straight line passing through its centers of pressure.

3. The combination. of a frame; a jaw having a concave surface journaled in the frame; a lever having a fulcrum in the frame; said lever having a convex face; a roller held by friction between the concave surface of the jaw and the convex face of the lever; means for oscillating the lever; said roller being located near to the lower end of the jaw and substantially vertically under the journal, whereby a line Passing through the centers of pressure on the roller will also substantially pass through the lower end of the jaw.

4. Thecombination of a frame; a jaw having a concave surface journaled in the frame; a lever having a convex face fulcrumed in the frame; a' roller mounted loosely between the said concave surface and the said convex face; a plate secured to the jaw to facilitate the n ounting ofthe roller; and means for swinging the lever back and forth.

Signed at Stockholm Sweden this eleventh day of March, A. D. 1913.

TUBE GUSTAF RENNERFELT.

Witnesses:

MARGARET PRICE, A. YANSSON.

G'opies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

' Washington, I). 0. 

